In dual control aircraft utilizing mechanical linkage, the copilot's control column or stick is linked to the pilot's control stick so that both controls move together in a parallel manner. The dual controls are designed to allow either the pilot or the copilot to have full control over the aircraft at all times during flight.
In some aircraft having dual controls, such as helicopters and military aircraft, it may be advantageous to disengage the copilot's control stick from the pilot's controls during certain phases of the flight. For example, when the copilot is not actively piloting the aircraft, the copilot may be occupied with other tasks, such as navigation, radar operation, and computer system operation. While the copilot is performing these other tasks, inadvertent jolts or pressures on the copilot's control stick can cause undesirable and possibly unsafe inputs to the aircraft flight controls. Because this problem can affect flight safety, copilot control sticks have been designed to be disengageable from the aircraft flight control system.
Disengageable copilot control sticks, which are designed for convenience and safety, can become a safety hazard if they are slow or difficult to reengage, or if it is possible for them to become jammed while being reconnected with the aircraft flight control system. During aircraft flight with the copilot's control stick disengaged, any malfunction of the stick-throttle interconnect (i.e. the pilot) may necessitate rapid reconnection of the copilot's stick so that the copilot can regain control of the aircraft.
Disengageable copilot control sticks currently available have not been totally satisfactory because they are difficult and/or slow to reengage and because they can become jammed during reconnection if the copilot attempts to apply any force to the stick before it is fully connected. Some disengageable copilot sticks utilize a ball or stud which is spring-loaded into a socket at the bottom of a bowl or inverse-conical shaped receptacle. These sticks are disengaged by overcoming the spring force to remove the ball or stud from the socket in the bottom of the bowl. Reconnection of these control sticks is accomplished by allowing the spring to urge the ball or stud down the sloping sides of the bowl and into the socket. However, reconnection cannot be accomplished if the copilot applies a force to the copilot's control stick counter to the force applied through the pilot's stick. Furthermore, the bowl-shaped receptacle is particularly suited for catching dirt and foreign objects that can jam the ball or stud and prevent its reinsertion into the socket of the receptacle.
Thus, a need has been identified for a disengageable copilot control stick that can be rapidly reconnected to the aircraft flight control system. Such a control stick should also provide some degree of aircraft control before it is fully connected, should not provide a catch-basin for dirt and other foreign objects, and should not become jammed during reconnection even if the copilot inputs control stick forces counter to those of the pilot.